Insertion of medical devices through non-orthogonal and orthogonal trajectories within the cranium and methods of using

Abstract

The invention comprises an elongated device adapted for insertion, including self-insertion, through the body, especially the skull. The device has at least one effector or sensor and is configured to permit implantation of multiple functional components through a single entry site into the skull by directing the components at different angles. The device may be used to provide electrical, magnetic, and other stimulation therapy to a patient's brain. The lengths of the effectors, sensors, and other components may completely traverse skull thickness (at a diagonal angle) to barely protrude through to the brain's cortex. The components may directly contact the brain's cortex, but from there their signals can be directed to targets deeper within the brain. Effector lengths are directly proportional to their battery size and ability to store charge. Therefore, longer angled electrode effectors not limited by skull thickness permit longer-lasting batteries which expand treatment options.

Description

BACKGROUND[0001]1. Field of the Invention[0002]The present invention relates to medical devices, systems and methods for accessing cranial and intracranial structures. Specifically, the invention is directed to altering brain function and treating cranial and intracranial pathology. More specifically, the invention is directed to the surgical implantation of electrodes or other devices within or through the cranium to alter or improve brain function and pathological states such as stroke, seizure, degeneration, and brain tumors. Most specifically, the invention is directed to minimizing surgical methods and risks and maximizing the length of devices that can be implanted within or through the cranium and their ability to hold charge.[0003]2. Description of the Related Art[0004]Electrical stimulation of the brain can improve and ameliorate many neurologic conditions. Examples of the success of brain stimulation include deep brain stimulation for Parkinson's Disease, tremor, dystonia,...

AI Technical Summary

Benefits of technology

[0032]The thickness of the cranium is limited to a length of 5 mm to 10 mm. If electrodes are inserted straight down, perpendicular (orthogonal) to the surface of the cranium, their lengths would be limited to a maximum of approximately 1 cm. Electrodes longer than 1 cm that are implanted in the cranium orthogonally would protrude through the skull into the brain. Placement of electrodes into brain substance increases the risk of injury to brain and blood vessels both during the time of placement as well as afterwards given the physiologic pulsation of the brain in relation to the cranium as well as during episodes of head trauma which causes acceleration and deceleration movement of the brain in relation to the cranium. Current methods of cortical stimulation place electrodes either epidurally (outside the dura mater) or subdurally (in between the dura mater and arachnoid or epi-arachnoid). Placement of electrodes in either of these locations provides for low impedance stimulation of the brain while maximizing safety. Current methods of placement of cortical electrodes necessitates drilling of a burr hole or craniotomy, both of which pose risks to the patient and commonly require a stay in the intensive care unit to monitor postoperatively.

[0033]The current invention describes the method of insertion of devices and electrode units through orthogonal and nonorthogonal trajectories through the cranium. Angled insertion of the electrode units enables longer units (length greater than skull thickness) to be used without penetrating into the brain. The angled electrodes pass almost entirely through the skull and then just barely protrude towards cerebral cortex. Longer electrodes units are desirable because the length of a battery is proportional to the size and capacity of the battery. Thus longer electrode units can contain longer and larger batteries. Preferably, the batteries are rechargeable. However, regardless of whether the batteries are rechargeable, it is desirable for the stimulation electrodes to have a maximum battery capacity (time until replacement or recharging). Higher capacity batteries provide sustained therapy and enhance patient mobility and freedom. The greater mobility and freedom provided by higher capacity batteries in longer electrodes increases the probability of patient compliance for out-patient procedures because it is e

Problems solved by technology

In deep brain stimulation, the electrode passes through the cerebral cortex as well as subcortical brain structures to reach the affected deep brain nuclei and therefore risks injury to the intervening healthy brain tissues as well as blood vessels.

These unnecessary yet unavoidable injuries can potentially result in loss of brain functions, stroke, and intracranial hemorrhage.

Although noninvasive, brain-machine interface using EEG signals is currently limited from the significant dampening of the brainwave's amplitude by the cranium.

These procedures necessitate a minimum of an overnight stay in the hospital and pose risk to injury of the brain due to the invasiveness of the techniques.

Additionally these “open” techniques pose special challenges for securing the electrode as most technologies require a lead to exit the hole in the skull.

Current techniques for cortical stimulation also risk the development of scarring of the cortex as well as hemorrhage.

Scarring distorts the normal brain architecture and may lead to complications such as seizures.

Additionally, the placement of devices on the surface of the brain poses risks of hemorrhage.

Thus in the case of a deceleration injury like that seen in traffic accidents or falls, the imperfect anchoring of the electrode and the mass of the electode may cause the el

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